Sir Ian Blair will again find himself fighting to keep his job today when an official report into the shooting of Jean Charles de Menezes highlights multiple errors that led to his death and identifies 15 areas where police must change to prevent a repeat of the tragedy.

The report by the Independent Police Complaints Commission (IPCC) will intensify the pressure on the Metropolitan police commissioner to resign, and will also criticise Sir Ian's decision to try to scupper their independent investigation into the shooting by asking the home secretary to block it.

Today's report will make no recommendation that Sir Ian should consider his position. But it contains 16 recommendations for operational changes to improve public safety in future anti-terrorist operations. They include calls for the urgent introduction of police radios which work underground, and criticism of flaws in the police command structure.

Appearing before the London Assembly yesterday, Sir Ian said 14 recommendations had already been put into operation.

Cressida Dick, the commander on the day of the shooting, will also be criticised by the IPCC, though the Metropolitan Police Authority has already decided she should not face a disciplinary hearing.

Yesterday Sir Ian became the first commissioner of the Metropolitan police to be told by London's elected body that he had lost their confidence and should quit. The London Assembly voted by 15 to 8, with the Tories and Liberal Democrats calling for him to go, and Labour backing him.

The assembly has no formal power to remove Sir Ian, but he spoke in detail for more than 100 minutes about what factors would lead him to resign, and faced withering attacks on his competence and abilities. At one point Sir Ian told a Tory critic, Richard Barnes: "This conversation does not take us any further. I have stated my position. If you have the power to remove me, go on."

The assembly's vote followed the Met's conviction for "catastrophic" errors that led to Mr de Menezes being mistaken for a suicide bomber on July 22 2005 and shot seven times at Stockwell tube station.

Home secretary Jacqui Smith yesterday reiterated the government's support for Sir Ian, who acknowledged that the loss of that support would be fatal for him.

Ms Smith attacked her Tory counterpart David Davis, saying: "It is completely wrong to politicise the future of an independent police commissioner."

London mayor Ken Livingstone, also backed the commissioner. "For as long as Sir Ian Blair continues to deliver the fall in crime and the very impressive work on defeating terrorism then the home secretary and myself continue to say he's doing a good job," he told BBC Radio 4's PM. "Almost nobody is aware of who any member of the assembly is. They make MPs look like household names."

Sir Ian told the assembly he would not resign because the failures were not "systemic", but limited to the operation that misidentified the 27-year-old white Brazilian as an East African terrorist suspect believed to have tried to bomb an underground train the previous day.

Sir Ian said "other forces" were orchestrating the campaign against him, an apparent reference to opposition to him being politically motivated. He said: "I have faults, I make mistakes. I don't particularly want to list them again ... You can read them anytime in the Daily Mail or Daily Express."

He said he would be letting down his successor if he was "driven from office by people who do not understand the facts and have a completely different agenda".

Sir Ian added that he would resign if he felt he had lost the support of his officers or had been rendered ineffective, neither of which was the case, he claimed.